Chusetts



J. H. GRAVELL.

TRANSFORMER SECONDARY.

APPLICATION FILED NOV. 23, 1 918.

Patented July 8, 1919.

A TTORNEYS UNITED STATES PATENT OFFICE.-

JAMES H. GRAVELL, OF BROOKLYN, NEW- YORK, ASSIGNOR TO THOMSON ELECTRIC WELDING COMPANY, OF LYNN, vIll/IIASS.ACI-]."[J'SE'1TS, A CORPORATION OF MASSA- CHUSETTS.

TRAN SF ORMER-SECO NDARY. I

To all whom it may concern:

Be it known that I, JAMES H. GRAVELL, a citizen of the United States, and a resident of Brooklyn, in the county of Kings and 'State of New York, have invented certain new and useful Improvements in Transformer-Secondaries, of which the following is a specification.

This invention relates to electric metal working apparatus and particularly to the transformer secondary construction for such apparatus in which the heat is developed in the work to be operated on by means of powerful electric currents set up in the transformer secondary. I

The object of the invention is to provide an improved form and arrangement of transformer secondary for such apparatus.

One of the most desirable forms of secondary for transformers used in this class" of apparatus. is known as the flexible secondary and consists of a bar composed of thin laminated copper strips threading through the core of the transformer and connected at its ends to work platens or large blocks of copper or other good conducting material forming the opposite terminals of the secondary circuit. construction avoids the use of sliding contacts in the secondary circuit which are objection-able in an electric metal working machine.

As the laminated secondary must have binding blocks at each'end to secure it to the platens, considerable space between the platens and the transformer is required thus lengthening the leads from the transformer to the platens and the machine cannot be made as compact as it should beto secure the best electrical result, Another disadvantage of the laminated "secondary is that no water circulation can be provided through According to my invention I am enabled to make a welding machine more compact and thereby improve the power factor by bringing the transformer close up to the platens and at the 's'ame time a water circulation is provided through that part of the secondary which threads the core.

The advantages gained by a construction .made according to the present invention very high.

Specification of Letters Patent.

This

Patented July 8, 1919.

Application filed November 23, 1918. Serial No. 263,798.

2. The cost of the apparatus is cheapened by providing a very short flexible part.

3. The machine is kept at a comparatively low temperature owing to the water circulation passing directly through that part of the secondary which passes through the core.

4. There is no wear on the primary coils due to mechanical movements of the sec ondary and therefore the insulation between the primary and the secondary may be reduced to a minimum.

The invention, consists in the improved construction of transformer secondary here-' inafter more particularly described and then specified in the claims.

In the accompanying drawings:

Figure l is a side elevation of a transformer constructed and arranged in accordance with this invention.

Fig. 2 is an end elevation of the same. 7

1,1 indicate the platens of an electric metal working machine. The platens, as is usual, form, theterminals of the secondary of an electric heating transformer and are provided with work-holding or wor -engaging devices of any'desired character as will be readily understood by those skilled in the art.

'2 indicates one leg of the secondary and extends from and is preferably cast or formed integral with the platen 1 and terminates in a leg 3 which passes through the connections 7 8 for supplying the cooling medium. I 7

By this construction the secondary may be brought close up under the platens and the said platens are preferably T-s-haped as shown in Fig. 2 so that the primary coils 9 on each side of the secondary may be accommodated and make the platens an active part of the secondary circuit.

In the operation of the machine either or both of the platens may be movable but preferably the platen 1 is rigid during the upsetting movement and'the primary coils 9 are clamped tightly against it and the legs or extensions 2, 3, but separated therefrom by insulation 10.

The flexible leg 5 is of suflicient length to permit the necessary upsetting movement of the platen l and is preferably slightly narrower, as indicated in dotted lines in Fig. 2, than the width of the legs 3 and 2- so that it will not bind against the primary coils. e

It will be understood that the construction may he modified in its mechanical details without departing from the spirit of the invention as expressed in the following claims.

What I claim as my invention is 1. In an electric i'netal working apparatus, a transformer secondary comprising a cast extension from one of the platens threaded through the core and a flexible connection from the end of said cast extension to the other platen. i

2. In an electric metal working apparatus, a transformer secondary comprising an extension integral with one platen and threaded through the core and a flexible leg connecting the end of said extension with the other platen, said extension passing through the core being-provided wit-h a passage for a cooling medium. a

3. In an electric metal working apparatus, a transformer secondary comprising a cast extension from one of the platens of the apparatus, said extension having a part threaded through the core, a flexible connection from said extension to the other platen and primary coils embracing said secondary and the platens.

at. An electric metal working machine having two work-platens, one of said platens having an integral extension threaded through the core of the transformer, a flexible connection between the end of said extension and the other platen and primary coils embracing said extension as well as the platens as and for the purpose described.

Signed at New York, in the county of New York and State of New York, this 19th day of November, A. D. 1918.

JAMES H. GRAVELL.

-Witnesses:

C. F. TISCHNER, IRENE LEFKOWITZ. 

